PERFORM NECROPSY WHEN CAUSE OF DEATH IS UNKNOWN

by: Heather Smith Thomas

If an animal dies and the cause of death is unknown, it often pays to have your veterinarian perform a necropsy to try to determine what happened, especially if a change in management could eliminate the risk for further deaths in the herd. A post-mortem examination might determine whether the animal died from hardware disease, pneumonia, poisoning or some other problem that might be preventable. If there's a disease in the herd (or a parasite problem or nutritional deficiency) that the producer has not been aware of, a necropsy can be a useful tool for helping solve a problem and improve health management.

Dr. David J. Steffen, Veterinary Diagnostic Center, University of Nebraska-Lincoln, says he is a firm believer in the value of accurate recording of mortality. “For large operations, it makes sense to have the veterinarian teach the basics of post-mortem examination to the herdsman, so deaths can be classified as respiratory, enteric, nutrition or something else—depending on the production stage or age of the animal involved. Many feedlots already do this. An accurate accounting of mortalities can flag problems and signal a need for review of health programs. The necropsy serves as quality control for clinical assessments and treatment protocols,” says Steffen.

“The veterinarian's role is in training and quality assurance for tracking the occasional mortalities, and for consultation when mortality numbers spike to a point where intervention is needed,” he says. In these instances the veterinarian may need to help with adjusting the treatment and management protocols.

“If animals are dying, the producer needs to keep good records and know how many have died. There's a certain threshold for different production phases, for anticipated death loss,” he says. No matter how well you manage the cattle in a cow-calf operation, for instance, there will be a certain number of calves lost to scours or some odd situation (hairball, calf stepped on by the cow, etc.). If the number of calves lost begins to exceed the “average”, then it's time to take a closer look.

“Your veterinarian or an animal scientist can come up with what those benchmarks should be for your production operation and situation. If you have records you can look at the losses in previous years and set a goal for improvement—or if it's a low level try to maintain that low level,” says Steffen.

“When things begin to go awry, and death losses are above normal, the next step is to categorize them as to body systems involved, whether it's skeletal (like a fracture), or respiratory, or enteric (digestive tract). Most people can characterize things as to whether it involves the respiratory system or is an enteric disease,” he says.

The producer needs to know whether it's a situation that can be dealt with to prevent further losses—such as moving the cattle out of a certain pasture that contains poison plants. “In baby calves, if you have death losses from enteric diseases, there's probably a certain level that you must deal with every spring, but if all of a sudden you lose a couple of calves with neurologic signs you might have your veterinarian check them because you don't expect it in this age group. It might be lead poisoning or rabies, or something else you need to know about,” he says.

If you experience a higher than normal death rate in baby calves due to scours, you may want to find out what pathogens you are dealing with, to determine a better way to prevent and/or treat it. “An experienced producer usually has a fairly good idea, due to symptoms, and knows what category to put the death loss into, but it's still helpful to have a veterinarian open up the calf to make sure you have the proper diagnosis, because some calves with enteric disease can show neurologic signs if electrolyte imbalances are severe or they become septic and get meningitis,” he explains.

“A feedlot animal with acidosis might have an increased respiratory rate and you may mistake this for respiratory disease. So it might be important to know what you are dealing with.” Gut blockage and bloat in a calf may be due to a hairball, eating dirt, or enteric disease in which the gut shuts down, or an accidental torsion. A necropsy to find the true cause of death may give a producer peace of mind—to know that it was a one-time thing, affecting one calf, and not a contagious disease.

“There's always some regret when someone comes in and has lost their 5th cow and wants to know what's going on. We ask what they found with the first 4 and they say they didn't examine those.” They've lost that window of opportunity to have a better idea of what might be happening.

“It's good to sit down with your local veterinarian who knows your operation and establish thresholds for when you need to step in and take action. Abortions are a good example. You expect a certain number of animals in late gestation to slip their calves for whatever reason, but at some point you should become concerned—if the number increases above average incidence (more than 1 or 2 percent).”

Feedlots do necropsies more routinely than cow-calf producers, but there are times the cow-calf producer would benefit from doing them—rather than just dragging the dead animal away and never knowing the cause of death. “Some of the big feedlots have mortality events every day, and it pays to develop this skill, to at least open up the animal and feel the lungs to see whether it's pneumonia, and look inside the rumen to see if there's inflammation inside and overload,” says Steffen.

“If mortality is a rare event in your operation, developing this skill may not be worth it, but this is when you can call on outside expertise.” Some people are reluctant to call their veterinarian, but it often pays to do so, especially if more animals start dying. In that event, a producer might wish he/she had called for a necropsy on the earlier ones.







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